Question

In a test, a student scores 2 marks for every correct answer, and loses 0.5 marks for every wrong answer. A student attempts all the 100 questions and scores 120 marks. How many questions did he answer correctly

Answer 1

total no of examination is 200 marks

he obtained 120 marks

its means 60 question he will done

left question

)=100-60=40

negative marks =40×0.5

=20 marks

so 20 marks decreses=120-20 =100

but he gain120 marks

100 obtained he will done 60 question

1. marks obtained he will done 60/100

120marks obtained he will done60/100×120

=72 question is correct

if your answer is right pleasemark me branliest.

thanks

Answer 2

Answer:

Given,

score for correct answer = 2 marks

score lost for incorrect amswer = 0.5

number of questions attempt = 100

total score = 120

to find = number of correct questions

Explanation:

score for correct answer = +2

score for incorrect answer = -0.5

let the number of correct questions = x

let the number of incorrect questions = y

2x + (-0.5)y = 120. ---------(1)

x + y = 100

x = 100 - y

putting this value of x in equation(1), we get

2(100-y) + (-0.5y) = 120

200 - 2y - 0.5y = 120

200 - 2.5y = 120

200 - 120 = 2.5y

80 = 2.5y

32 = y

x = 100 - 32 = 68

Number of correct questions attempted = 68

Number of incorrect questions attempted = 32